Found a modern day field sequential color tv
 

Thought the members may be interested. Found a television that uses a 4.5 inch monochrome CRT as the image source. It produces a full color image with RGB liquid crystal filters that turn on and off sequentially. It uses field memory kinda like the old spinning color wheel concept but done electronically.

When viewing, it has high resolution. It has no phosphor pixels, dots or stripes. All you see is the barely visible scanning lines from the black and white CRT. Produces a very smooth unbroken color image.

:worthless

Heh heh. :)

Sorry. See the bottom of this link, year 2000.

http://www.visions4.net/journal/time...a/page-four-a/

Fascinating set! That was not sold in the USA market, I am guessing.

It appears to be a consumer application of the Tektronix Liquid Crystal Color Shutter (LCCS), introduced in the early 90s:

http://www.electronicproducts.com/Te...bandwagon.aspx

1986 patent: http://www.google.com/patents/US4582396

jr

It was sold to the professional market. My set has a built in NTSC tuner for VHF/UHF and it will decode PAL for the Euro market. If you Google the model number, you can find the complete owners manual. There were rack mount and field accessories.

Interesting, thanks for the info.

I called JVC and they sent me the complete service manual with schematics, exploded views, circuit boards and parts list. The set has 7 circuit boards, 43 IC's. I see a video processor, micro controller, video decoder and ASIC scan field converter 1X to 3 X. There must be tremendous switching going on and a built in fan activates when I switch on the power.

This set retailed for far less then the Textronic. I got it for a song. Don't think the seller new what he had or thought it was an antiquated.

But remember, the Tektronix application was very high performance digital oscilloscopes (BIG$$$) not television monitors.... Here is one on the 'bay:
http://www.ebay.com/itm/Tektronix-4-...item33925d996b

Not affiliated,
jr

Agreed. Here is the JVC press release: http://pro.jvc.com/pro/pr/nab/tml450tu.htm

Very cool indeed.

Thanks for posting. I feel like I should remember this, but I don't. I wonder how many they sold.

I posted a video today showing the JVC LCCS in operation.

http://m.youtube.com/watch?v=S5RChk3...ature=youtu.be

Excuse the commercial or skip over it.

If I am understanding this correctly, the LCD doesn't reproduce any video - it is acting as a replacement for the spinning color wheel. Would this be the correct assumption?

Yes. The three filters, RGB are being switched on and off sequentially according to video signal stored in field memory. They are located in front of the monochrome CRT. The switching is so fast that the eye sees a single color image.

Yes, I understand this part - Persistence of Vision. But this is true of all television and motion picture images.

Since the Screen is relatively small, and the CRT is hidden behind the LCD Panel - I would think that it would almost look as clear as watching projected film.

Yes. The first impression is a very smooth, clear, unbroken image. According to JVC the RGB filters are highly transmisive.

I have posted a high resolution screen shot. See below. Obviously many times original size so you can see that there are no pixel elements on the screen. The scanning lines from the monochrome CRT are very visible in this shot, but when you see it as it is, 4.5 inches, the scanning lines are barely visible. The resolution is rated 400 lines, not exactly HD, but looks very good.

http://www.visions4.net/journal/wp-c...dy-full-WP.jpg

So I was rummaging around in the library at my school today and look what I found while I was flipping through an issue of popular science! I believe this article was published in 2012, but I am not sure. The photos that I took of the articles didn't come out so I will not bother posting them unless someone want s them... This looks familiar? To me it looks like it is the same thing as what is being discussed here, only for use in new tablets..
I believe the title of the article was "Queen of the screen" if I am not mistaken...

With the exception of the scan lines, the color reproduction looks exactly like a photograph - and not a still capture of a color CRT image. Watching the YouTube did give the impression that I was watching a projected film on a screen, not a CRT - very impressive.

The smallest color CRT ever made was approximately 1.5" - Beam Index EVFs included. The smallest color LCD ever made is approximately .4" - also for EVFs. The smallest B&W CRT ever made also was approximately .4" - I know that this could never happen now, but this technology could have produced the smallest color CRT based monitor using a .4" B&W CRT. I collect miniature CRT based TVs and EVFs - I would love to have 1 employing this technology!

I just bought one on the bay NIB! Been around for a few days. Very interesting design aside from the field sequential. It has a RF input for VHF/UHF on the backside so it looks like it has a tuner inside. It also has all the pro settings needed. Blue only, 16x9, underscan, etc. It needs a 4-pin DC source but also has a mini 1/8 connector input for power. Not sure of the amps needed for the mini. This will be fun.

A bit more searching and it looks like the mini is from a factory AC adaptor at around 2.5amps. Hoping a laptop brick can do the trick otherwise I will use my Sony 4pin from 1978.

Dave,

Great!
The factory AC adaptor is model # ADP-50VP which is attached to mine. Possible that JVC may still have one in stock. I have a complete service manual if you need one. Just contact me.

I picked up 1 of these from the same seller - it did not have the AC Adapter attached. this was listed as "NEW" - the listing states that it weighs 7.5 lbs with it's AC Adapter, the manual states that it comes with the AC Adapter. He clearly stated that it did not come with a 12V 4 pin Power Supply, but he did not state that there was no AC Adapter. Also, there are some scratches on the front glass. But the most disturbing thing about this unit is the Volume is barely audible at the maximum level of 15.

I asked him about this, and he responded:

"Hello: I did not mentioned any other power supply that is included and I don't have any, I just see that it has the 4pin power input and I mentioned that I do not have the power supply, sorry about that, all as pictured is included,what not pictured is not included,Thank you again"

This is the text from the listing:

JVC TM-L450TU LCCD 4.5" Professional Field Video Monitor , NEW!!!
will works with12v 4pin power supply (not included)

4.5" Liquid Crystal Color Shutter (LCCS), CRT Color Monitor - TM-L450TU

This super bright, super high resolution portable 4.5" LCCS color monitor is from JVC. This highly compact triple EIA rack-mountable monitor weighs less than 7.5 pounds with its AC adapter. It utilizes Liquid Crystal Color Shutter (LCCS) technology, which unlike a conventional CRT monitor utilizes a combination of a black and white CRT with a liquid crystal color shutter. Sharp images are displayed in even the brightest enviornment, without misconvergence or annoying moire patterns. It features over 400 TV lines of resolution, dual NTSC or PAL inputs and an intergrated NTSC TV Tuner with RF channels VHF 1-12 and UHF 13-62. The display size is adjustable for overscan, underscan and 16:9 aspect ratios. It has blue only mode for color phase adjustment. This monitor offers twin loop through BNC Video with mono RCA Audio inputs plus an RF antenna input (75 ohm F connector). Additional attributes include an easy adjustment and set-up OSD menu that includes contrast, brightness, sharpness, chroma, phase, video system, power save mode and channel settings. It has a built-in handle to make it easy to transport the monitor wherever you go. The handle can be removed for rack mounting. A built-in stand folds out from the bottom of the monitor, allowing the it to tilt upwards approximately 18 degrees.

AN item listed as "NEW" on eBay is stated as:

New: A brand-new, unused, unopened, undamaged item in its original packaging (where packaging is applicable). Packaging should be the same as what is found in a retail store, unless the item is handmade or was packaged by the manufacturer in non-retail packaging, such as an unprinted box or plastic bag. See the seller's listing for full details.

This should never have been listed as "NEW"!

etype2 - your posting said that it was sealed in the box and included the AC Adapter.

Dave A - please let me know what condition yours is in, and if it included the AC Adapter. (This will work with a laptop brick rated at 19V and at least 2.5A)

etype2 - would it be possible for me to get a copy of the service manual from you?

crtfool,

Glad you got one. Mine was definitely new. It was sealed in an unopened factory box with the styrafoam shipping material. The AC power supply was attached to the back of the unit and both, including the manual were sealed in unopened plastic bags. The receiver on my unit also had a peel off cellophane protector on the glass screen. Brand new no scratches or blemishes. See photo.

Yes, send me your contact information and I will send you a PDF of the service manual.

AC power adaptor photo: http://s184.photobucket.com/user/ety...pg1-5.jpg.html

http://www.visions4.net/journal/wp-c...eq-full_WP.jpg

Mine arrived today in the same condition CRT described. Opened as stated in the listing and also missing the AC adaptor. Mine also has minor scratches on the front plastic screen cover but not another scratch. Nothing that Novus #2 would not cure. Having read the sellers listing I got what I expected and did not want to challenge him. I will deal with it...unless he tries to sell adaptors separately. Stay tuned.

An old Gateway laptop brick popped it right to life out of the box with no video connection. It is a cute little thing from 2000. Just pushing buttons showed a 2-69 tuner inside with a scan available. Too bad nothing to scan but a dedicated RF source if needed. The surprise was the video input was set to PAL and no switch to NTSC. Rats. I also suspected this was a factory default and some local sensing was onboard. Correct. Hooking my DVD to the set flipped the input to NTSC and all was well. The audio was dreadfully low from the speaker but with earphones it was fine. This set was a field set and you would have been on phones anyway.

I played some old TK stuff I have on DVD and was pleased although it was not as sharp as a modern signal and a few generations old. The old TK color on-screen was a bit subdued from what we are used to. It is not lollipop color unless you crank it way up but very normal looking. It did seem to have trouble with flares in the lighting and they showed as offsets from the flare as a separate red trace. The BW setting showed mine needs a bit of blue gain needed.

Etype...I could use the manual to fix the gains.

I took a bunch of photos and they were hard to do to show the pix given the low light. I loaded a few. They are more true color because of the camera. The real screen pix is a bit warmer...missing a bit of blue...and my camera fixed that by itself.

While taking the pix I got a few photos of the R or G or B image by accident. I could also see the RGB by doing the old fan-your-fingers past the screen and see the artifacts. Much like the old white baseball flying through the shot as separate RGB colors on mechanical sets.

Overall, I am glad I got it. It is a bit of ancient technology that JVC dusted off 50 years later for who knows why. What were they thinking other than a higher definition field set that showed color? And who owned the patent at this point?

Dave A,

Glad you got one. Like the Dean Martin shot.
I think it's neat to have a modern day field sequential set, like it for its uniqueness. I see no way to adjust the saturation or hue because it is just a black and white CRT with fixed color filters. Am I wrong? Think it was meant to be fixed. Send me your contact information and I will send you the PDF service manual.

etype, the set is very adjustable in the menu. Click through and use the volume +- to adjust. Most default settings are 0. Change at will. Have at it. If you use PAL in Silicon Valley then it is not adjustable but then Silicon Valley is very different. I will PM for the manual.

Dave A,

Your right, it's the Chroma. Just assumed it couldn't be adjusted because the CRT is b/w.

JVC always seems to do things a little differently. Isn't this also how the DLP projection TVs that were sold 10 years ago worked?

This JVC is different. It uses a 4.5 inch monochrome CRT as the image and light source with RGB filters and polarizers. The old DLP sets used a DLP chip, the color wheel and a light source such as a high intensity projection lamp.

The color wheel in DLP is similar in concept to this LCCS because they both rely on persistence of vision in the human eye to create the single color image.

I took mine to our DVHRC monthly meeting tonight for opinions on how it works and I got a bunch of input. I had not looked at the manual much since this started and we looked around.

The first thing spotted is that the CRT...all 4.5"...operates at 12kv. That is a lot for a mini monitor but this set was sold as a daylight useable monitor. Bright outside with high resolution. That helps explain the 12kv and also the CRT having to be bright behind a bunch of dark LCD filters. The "blue only" button on the front gives a true view of the blue image as it passes. The R and G should be the same and as dark.

And hidden in the block diagram is a square noting the "sports killer" in the V blanking box. Our translation specialists converted this to "shorts killer" which makes sense. Kill the beam on a sweep failure at 12kv so a single beam sweep does not laser off your arm.

The next question was how do they do the RGB at the tube to sync with the RGB LCD in front of the BW tube.

The block diagram suggests video buffers ahead of the CRT and sideways to the LCD shutter conversion to be re-combined later in front of the screen. 1gig worth at the CRT. 512 at the LCD conversion. We think the buffers show the video on each frame in sequential RGB at the CRT to sync with the LCD doing the same. The LCD takes over from there to make color minus all the artifacts of NTSC. So clean and pure.

We think that the usual 30 frame/sec rate is tripled so each frame can do the RGB information at the tube inside 1/30 sec. That means this set does 90 frames per second via the buffers at the CRT to get you a complete RGB color frame in 1/30th of a second for the LCD to parade along with at the same rate.

Comments welcome.

JVC's literature says that the signals in the field memory are read three times faster than the input video signal and sent to signal processing, ultimately to the two liquid crystal shutters. The Sync. input is 50HZ x 3 = 150HZ. The black and white CRT frequency is 15.625 x 3 = 46.875 kHZ. One field displays 3 images (RGB) in 1/50th of a second.

JVC says the three color RGB filters are crystal clear.

Peter Goldmark from CBS had a good idea back in the 50's. If this technology were available then, we would not have the tricolor phospher shadow mask CRT. The elegant simplicity of a single gun monachrome CRT, requiring no convergence adjustments, no effects from magnetism or moire effects. High resolution, very bright film like images with no distracting color phosphor dots or stripes on the screen.

Scratching my head over that one, while the transmission of each filter might be fairly good at the selected color, the transmission of white field through the entire stack of filters, cells and linear polarizers is likely less than 20%, if it is anything like the Tektronix LCCS design. The CRT in the Tek scopes, without the LCCS stack was quite bright!
Also IIRC, the Tek design actually used magenta, yellow and cyan filters, so perhaps JVC improved in the design?

jr

A portion of text taken from JVC brochure:

"Unlike a conventional CRT screen, where the picture is written on the back of a light-absorbing layer, the TM-L500PN features a bright backlit screen seen through crystal-clear filters. Even if ambient light shines on the screen, the picture loses none on its contrast or clarity."

Maybe taking a bit of liberty here in their description.

BTW, what does IIRC mean?

See this all the time in this forum, but have been embarrassed to ask. I get what IMHO means. LOL. (old guy here)

Google knows all, and I consult them if I don't know a word or abbreviation....That said IIRC = If I Recall Correctly.

If I remember correctly, it means "if I remember/recall correctly". :)

jr

Cfm tu :-)

Unless they are converting form NTSC to PAL there is no way it could have 50Hz synch....59Hz I'd buy, but 50Hz no way.

A few observations and questions...and thanks for the input from all with a few photos added tonight to hopefully help me figure this out.

Jr...The first is that the LCD shutters are variable in chroma density on this set depending on the user menu chroma setting. Not fixed color filters like a DLP or a Col-R-Tel. When I got this and the manual, I found the RGB shutter gains...on the side of the body...and did a by-eye setup to BW with the chroma down. It is as close as it gets to BW by my aging eyes. The camera white balance is a bit off. BW here. The shutters look clear at this point and it shows the finest scan lines I have ever seen. I can shine a flashlight through the front and easily see the CRT. 100% transmission to me in BW. The addition of color will change that to the users degree of chroma gain.

I added a "blue check" menu button photo from the front button selection. "Blue check" is an old, cheap way to set bars on a color monitor without a scope. This should also represent a frame/field of the blue processing and does show the luminance values in the blue space for it's moment in RGB color. R and G should be the same and sequentially add to balanced color in the scan at that moment. And your persistence of vision kicks in at this point.

etype...you mention two filters and the block shows one eprom going to two buffers before the LCD shutter. Is this not RGB or am I missing something? The video buffer shows two dram. Is this some kind of color +/- thing going on? Help me with the two shutter concept.

And help me more with the scan/field rate. I think I am close but a blow-by-blow of a frame in RGB/LCD processing would help.

Gotta go now so I can watch the 1960 Peter Pan in JVC field-sequential color. I am seeing colors I have never seen before.

Hi to All,

For those who have not downloaded/watched the JVC's advertising brochure, here are zoomed shots showing the LCD color shutter system.

Note the use of the term LCCS in the 3rd slide, therefore implying direct parenthood with the Tektronix color oscilloscope technology.

As for the switching speed, my opinion is that it is always 3x the incoming signal frequency, therefore 3x60 in NTSC, 3x50 in PAL.
Being a digital design, no problem there.

Best Regards

jhalphen
Paris/France

Link to a patent application:

http://www.google.com/patents/EP0157523A2?cl=en